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How the CVE Works
CVE-2025-49709 is a memory corruption flaw in Firefox (< 139.0.4) caused by improper handling of certain canvas operations. Attackers could exploit this by crafting malicious web content that triggers undefined behavior in the browser’s rendering engine, leading to arbitrary code execution. The vulnerability stems from insufficient bounds checking during canvas manipulation, allowing heap memory corruption. Successful exploitation could result in full system compromise under the user’s privileges.
DailyCVE Form
Platform: Firefox
Version: < 139.0.4
Vulnerability: Memory corruption
Severity: Critical
Date: 06/16/2025
Prediction: Patch by 07/01/2025
What Undercode Say
Check Firefox version
firefox --version
Exploit PoC (hypothetical)
<canvas id="exploit"></canvas>
<script>
let ctx = document.getElementById("exploit").getContext("2d");
// Malicious canvas ops triggering corruption
</script>
How Exploit
- Craft malicious HTML with corrupt canvas operations.
- Trigger heap overflow via rendering engine.
- Execute arbitrary shellcode.
Protection from this CVE
- Update to Firefox ≥ 139.0.4.
- Disable JavaScript (mitigation).
- Use sandboxed browser profiles.
Impact
- Remote code execution.
- Full system compromise.
- Bypass security boundaries.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
